Ram boring machines, also known as earth rockets, are mainly used to lay supply lines for water or electricity and telephone cables without having to tear up the road surface or the sidewalk. They usually have an impact tip acted on by a pneumatically operated impact piston. To drive the impact tip forwards the impact piston is reciprocated in a tubular housing by the action of compressed air supplied through a compressed air line alternately on the front and rear faces of the impact piston. Openings through the rear end of the housing allow the exhaust air to emerge into the tunnel made in the ground by the boring machine, and from there into the open air.
In the case of ram boring machines, as with most compressed air machines, lubricants, e.g. mineral oil or other additives are mixed with the compressed air. These additives emerge into the open air with the exhaust air as mist, and represent a danger to the operator and the environment.
The noise produced by most ram boring machines is often above the level of 90 dBA that in the long term is a danger to health. This level is mostly exceeded even in the case of a ram boring machine that operates predominantly below the surface of the earth. Particularly when a supply pipe is drawn in simultaneously with the ramming, a considerable amount of noise gets through to the exterior, since the pipe acts as a sounding pipe.